Communication method and apparatus

Abstract

A method includes: A first node sends a threshold and a first packet to a second node. Correspondingly, the second node receives the threshold and the first packet from the first node. Then, the second node determines first channel state information CSI based on the first packet. If a change amount of the first CSI relative to preset CSI exceeds the threshold, the second node sends a second packet to the first node. If the change amount of the first CSI relative to the preset CSI does not exceed the threshold, the second node does not need to send the second packet to the first node. The method is applied to a radio sensing process.

What is claimed is: 
     
         1 . A communication method, comprising performing radio sensing by steps of:
 receiving, by a second node, a threshold and a first packet from a first node;   determining, by the second node, first channel state information (CSI) based on the first packet; and   in response to a change amount of the first CSI relative to a preset CSI exceeding the threshold, sending, by the second node, a second packet to the first node, wherein the preset CSI is a CSI previous to the first CSI determined by the second node;   wherein sending, by the second node, the second packet to the first node in response to the change amount of the first CSI relative to the preset CSI exceeding the threshold further comprises:   receiving, by the second node, a measurement query request from the first node;   in response to both the measurement query request and the change amount of the first CSI relative to the preset CSI exceeding the threshold, sending, by the second node, an acknowledgment (ACK) message to the first mode, wherein the ACK message indicates that the second packet is to be fed back to the first node; and   after the second mode receives a measurement trigger request from the first mode, sending, by the second node, the second packet to the first node.   
     
     
         2 . The communication method according to  claim 1 , wherein the measurement trigger request further indicates a spatial flow for transmitting the second packet; and
 sending, by the second node, the second packet to the first node further comprises:   sending, by the second node, the second packet to the first node by using the spatial flow indicated by the measurement trigger request.   
     
     
         3 . The communication method according to  claim 1 , wherein the measurement trigger request further indicates a subchannel for transmitting the second packet; and
 sending, by the second node, the second packet to the first node further comprises:   sending, by the second node, the second packet to the first node through the subchannel indicated by the measurement trigger request.   
     
     
         4 . The communication method according to  claim 1 , wherein in response to the change amount of the first CSI relative to the preset CSI exceeding the threshold, sending, by the second node, the second packet to the first node further comprises:
 receiving, by the second node, first indication information from the first node;   in response to the change amount of the first CSI relative to the preset CSI exceeding the threshold, obtaining, by the second node, a target channel based on the first indication information through channel contention; and   after the second node sends a null data packet announcement (NDPA) to the first node through the target channel, sending, by the second node, the second packet to the first node through the target channel, wherein the NDPA indicates that the first node is to perform CSI measurement.   
     
     
         5 . The communication method according to  claim 1 , wherein the threshold is carried in the NDPA or a query frame. 
     
     
         6 . The communication method according to  claim 5 , wherein the threshold is carried in some bits other than an associate identifier (AID) in a station information field of the NDPA, and a value of the AID in the station information field is an identifier of the second node; and
 when a sounding dialog token field of the NDPA indicates that the NDPA is used for ranging, the threshold is carried in a user information field of the query frame.   
     
     
         7 . The communication method according to  claim 1 , wherein the first packet is a null data packet (NDP), a physical layer protocol data unit (PPDU), or a data packet that carries a training symbol; and
 the second packet is an NDP, a PPDU, or a data packet that carries a training symbol.   
     
     
         8 . A communication apparatus, comprising:
 at least one processor; and   at least one memory storing a program, wherein execution of the program by the at least one processor, causes the communication apparatus to perform radio sensing by performing steps of:   receive a threshold and a first packet from a first node; and   determine first channel state information (CSI) based on the first packet; and   in response to a change amount of the first CSI relative to a preset CSI exceeding the threshold, send a second packet to the first node, wherein the preset CSI is a CSI previous to the first CSI determined by the communication apparatus;   wherein the communication apparatus is configured to send the second packet to the first node by performing steps of:   receive a measurement query request from the first node;   in response to both the measurement query request and the change amount of the first CSI relative to the preset CSI exceeding the threshold, send an acknowledgment (ACK) message to the first node, wherein the ACK message indicates that the second packet is to be fed back to the first node;   receive a measurement trigger request from the first node; and   after receiving the measurement trigger request from the first node, send the second packet to the first node.   
     
     
         9 . The communication apparatus according to  claim 8 , wherein the measurement trigger request further indicates a spatial flow for transmitting the second packet and execution of the program by the at least one processor further causes the apparatus to:
 send the second packet to the first node by using the spatial flow indicated by the measurement trigger request.   
     
     
         10 . The communication apparatus according to  claim 8 , wherein the measurement trigger request further indicates a subchannel for transmitting the second packet and execution of the program by the at least one processor further causes the apparatus to:
 send the second packet to the first node through the subchannel indicated by the measurement trigger request.   
     
     
         11 . The communication apparatus according to  claim 8 , wherein execution of the program by the at least one processor further causes the apparatus to:
 receive first indication information from the first node;   in response to the change amount of the first CSI relative to the preset CSI exceeding the threshold, obtain a target channel based on the first indication information through channel contention; and   after sending a null data packet announcement (NDPA) to the first node through the target channel, send the second packet to the first node through the target channel, wherein the NDPA indicates that the first node is to perform CSI measurement.   
     
     
         12 . The communication apparatus according to  claim 8 , wherein the threshold is carried in the NDPA or in a query frame. 
     
     
         13 . The communication apparatus according to  claim 12 , wherein the threshold is carried in some bits other than an associate identifier (AID) in a station information field of the NDPA, and a value of the AID in the station information field is an identifier of the communication apparatus; and
 when the sounding dialog password field of the NDPA indicates that the NDPA is used for ranging, the threshold is carried in a user information field of the query frame.   
     
     
         14 . The communication apparatus according to  claim 8 , wherein the first packet is a null data packet (NDP), a physical layer protocol data unit (PPDU), or a data packet that carries a training symbol; and
 the second packet is an NDP, a PPDU, or a data packet that carries a training symbol.   
     
     
         15 . A non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores a program, and invocation of the program by a processor causes the processor to perform radio sensing by performing steps of:
 receive a threshold and a first packet from a first node; and   determine first channel state information (CSI) based on the first packet; and   in response to a change amount of the first CSI relative to a preset CSI exceeding the threshold, send a second packet to the first node, wherein the preset CSI is a CSI previous to the first CSI determined by the processor;   wherein the processor is caused to send the second packet to the first node by performing steps of:   receive a measurement query request from the first node;   in response to both the measurement query request and the change amount of the first CSI relative to the preset CSI exceeding the threshold, send an acknowledgment (ACK) message to the first node, wherein the ACK message indicates that the second packet is to be fed back to the first node;   receive a measurement trigger request from the first node; and   after receiving the measurement trigger request from the first node, send the second packet to the first node.   
     
     
         16 . The non-transitory computer-readable storage medium according to  claim 15 , wherein the measurement trigger request further indicates a spatial flow for transmitting the second packet and invocation of the program by the processor further causes the processor to:
 send the second packet to the first node by using the spatial flow indicated by the measurement trigger request.   
     
     
         17 . The non-transitory computer-readable storage medium according to  claim 15 , wherein the measurement trigger request further indicates a subchannel for transmitting the second packet and invocation of the program by the processor further causes the processor to: send the second packet to the first node through the subchannel indicated by the measurement trigger request.